Based on the number of new cases (incidence), non-Hodgkin lymphoma is an increasingly common cancer in Australia and many developed countries. Until recently, mortality trends have been stable or slightly increasing. However, since the year 2000, mortality has decreased every year by an average of 5.1% per year (95% confidence interval (CI) −7.1 to −3.1%), whereas incidence has continued to increase at 0.9% per year (95%CI 0.6 to 1.2%). It was not possible with the population-based registry data available to us to untangle the causes of the decrease in mortality. The stable mortality rates during the 1990s (in the face of increasing incidence) might have been because of introduction of novel therapies such as autologous stem cell transplant for relapsed diffuse large cell lymphoma or the purine analogue-based therapy for indolent lymphomas. A plausible explanation for the large decrease in mortality since 2000 is the introduction of the monoclonal antibody rituximab.